How to heal the holes left after deleting or moving an object?

I am attempting to draw exterior stairs that will be similar to the attached PNG file (but not identical). I have also attached my very “beginner” SketchUp drawing. I will have more questions later.

I’m sure I’ll have many more questions, but my first is classic newbie. But first, some background: I drew what represents “the ground” on the XY plane, and the wall of the house with the offset on the XZ plane. I then drew what will be an apartment entrance platform as a rectangle on that “ground” plane, pulled it up to 8" thick, and raised it to the proper building floor height.

Yes, I made the mistake of drawing that 6x6 (nominal, American) column that will support the corner first, and the platform rectangle later, so when I raised the platform it took the column with it. I still haven’t figured out how to move that column straight down, so I plan to delete it and draw it again at the correct height. I left the drawing “as is” because the next befuddling problem might have some benefit also. So on to my actual question:

When you draw on an existing surface such as my “ground”, and then manipulate that (a rectangle turned polyhedron and elevated on the Z axis in this case), it creates a hole in the original surface. How do I heal that hole? (or those holes, because in my drawing, I have also deleted a simple rectangle in that surface, which created another hole).

As a separate question: Are there benefits to leaving those holes until later as an aid for drawing? The more I think about this, the more I think not. I deleted that rectangle because I accidentally drew all 4 too large. I plan to redraw a smaller rectangle and try the copy/paste function to replace all 4 (after deleting the others and healing the surface).

Basic geometry testing.skp (195.9 KB)

Thank you,

You can “heal” the holes by redrawing the shared edge to complete the surfaces. Then simply erase the extra lines.

Your column won’t move down because it has been set to glue to a surface, right click and unglue first. Then use the move tool to move it down, lock the inferencing to blue axis with the up arrow on your keyboard if you wish

Blue Grey faces in your model are inside out, you are looking at the back face of the surface. Select and choose reverse face.

I did this in pro, but although the interface is slightly different in web the actions and methods are the same.

Some good tutorials on SU for Web here: SketchUp Web Fundamentals


If you are isolating the geometry in your model by using groups and components as you should. Then there will not be any “holes” created, each new piece of geometry is it’s own separate unit.

It’s dinner time here, but I wanted to give you a quick reply. Thank you! Your short video (is it a GIF?) was crucial for understanding how to heal the surface. And your Unglue suggestion worked beautifully!

SketchUp Free (web version) doesn’t appear to have the Reverse Face option in the context menu, but frankly, I’m fine with the color issue and time is of the essence.

I have enrolled in the course, although I dread the prospect (the time issue). I am SO grateful for your help so that I can try to work through this as fast as possible.

I’m skipping your last comment until I’ve had time to learn more. It’s over my head.


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You shouldn’t, back faces can become problematic, sketchup won’t recognize it as a solid if you make a group or component, so you won’t be able to make Boolean operations, if you want to 3D print your object must be a solid piece, and if you want to render, the back faces will be shown as black faces.

I beg to differ.

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@Box : I see it does, thank you! It didn’t appear in the menu until I exploded the group. I have since re-grouped it.

Ok. even though I may not want to do any of those things with this particular drawing, I’ll follow your advice as good practice.

I’ve reversed the faces as @Box showed. Now I have another problem: the Push-Pull tool is avoiding my column when I try to pull it up to meet the bottom of the platform. I have preselected it, then switched to the tool, and the tool automatically jumps to other nearby surfaces (selects them) when I attempt to extrude the column. I have attached the current file.

Also, after following the advice of @endlessfix to heal the surfaces and erase some of the leftover lines, I noticed that for any lines drawn on a guide line, it erased both at the same time. Is there a way to force selection of just the leftover line, leaving the guide line? You’ll see in my drawing that I left some of the lines of the oversized rectangles to avoid deleting some guide lines that I’m not ready to dispose of yet.

@endlessfix : How do I make sure that I’m isolating my geometry as you stated? To create a column, I drew a rectangle on the “ground” surface and then pulled it up into a 3D column. What step did I miss that would have made it a separate piece of geometry?

Basic geometry testing.skp (186.8 KB)

Thank you all,

Update: I did discover that by ungrouping the column, SketchUp then allowed me to extrude it up to the platform bottom. I then grouped it again.

My other questions remain.


You should do a few of the tutorials, there are some basic concepts that it would benefit you to understand. In SketchUp all geometry, edges and surfaces, are “sticky”. Geometry merges together by default. To create geometry that acts as a discrete entity we wrap geometry in a “container”. These containers are called groups or components, each behave a little differently but they both isolate the geometry contained within from the rest of the model. Your column is a group, the geometry inside the group is isolated from the rest of the model and does not interact with it. This allows you to move it around as a separate entity. Groups and components are like wrappers in the sense that they contain the geometry within, but it is not necessary to explode or ungroup the group to gain access to the geometry within, simply open the group for editing. When you select a group or component it has a blue bounding box around it (unlike raw or loose geometry). Simply double click on the group or component (or right click and choose edit) to open it for editing, the bleu bounding box turns into a set of dotted lines and the rest of the model goes grey telling you that you are working inside the wrapper. To exit the group click once outside the bounds of the wrapper.

To push pull a surface on your platform, first open it for editing, then use the tool as normal. Same for reversing the faces.

Yes, instead of the eraser, use the selection tool to select only the lines you want to delete (hold the shift key to select multiple) then press the delete key.

Again, groups and components, a basic and fundamental part of modeling successfully in SketchUp. Without them your work in SketchUp will be tedious, slow, and frustrating. Investing one hour in the Campus course will save you 40 hours down the road.

@endlessfix : Thank you so much for that detailed explanation. I don’t think I could get such a concise explanation from any of the vast amounts of material on SketchUp out there, but I have downloaded the first course (Fundamentals) and started it. I did previously spend time watching a number of the official SketchUp videos on YouTube, which were helpful. Frankly, there is SO MUCH material out there, that I just don’t have time for it all. That meant “cheating” by asking you folks as a shortcut.

I’m grateful for the help. I will do my best to get up to speed ASAP to avoid pestering the forum. I’ll probably be back with another question(s) though, because I’m under such time pressure to get this project approved by the local building inspector and BUILT.

I would definitely consider paying hourly to have someone guide me through this drawing. Or should I say draw and explain it to me while I watch and give the necessary numbers?


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@BetaTestPrisoner There is indeed a lot of material out there to wade through, I believe you can’t do better than the Campus Web course and would stick to that. Just completing that short course will set you up very well. Please do come back and ask questions here on the forum, that’s what it’s here for. There are many generous, knowledgable users here that are happy to teach a man (or woman or other) to fish, as long as we’re not just giving out fish. :grinning: It’s best to start a new thread for each new question as that helps us keep the forum organized so each question is searchable with threads that have solutions which may be use-full for others.

See you around.

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Thank you again! It’s good to hear an experienced opinion about the best place to study; I’ll take your word for it. Thanks also for the tip regarding proper posting of questions - I have been unsure of proper etiquette.


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You should follow the free courses on the sketchup website. Those issues you’re having are easily solved if you know the basics of the program.

Thank you @francisquitof! I have already been pointed in that direction and have started the course materials.

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